I bought some casters for my Series One 45 combo and over time, they've started to get very loose in the sockets. I can't tighten them and I am assuming that the threads inside the caster sockets have started to wear away. Where can I get replacement caster sockets from in the UK so I can change the existing ones? I can't see anywhere on the site that sells spares parts like that nor can I find any on ebay? There are companies selling them in the US but not in the UK it seems.

I'm a bit concerned that eventually the casters are going to fall off completely while I'm wheeling the amp about.